Corporate Investments And Funds Held For Clients (Classification Of Corporate Investments On The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Corporate Investments And Funds Held For Clients [Abstract]
Cash and cash equivalents	$ 2,794.9	$ 1,639.3	$ 1,848.0
Short-term marketable securities	26.9	26.6
Long-term marketable securities	21.0	28.9
Total corporate investments	$ 2,842.8	$ 1,694.8